In an aircraft, hydraulic power is usually generated by engine driven hydraulic pumps connected to two or more hydraulic line systems. For the purpose of increasing the redundancy or the capability of compensating load peaks in the hydraulic power demand, additional hydraulic pumps may be provided driven by dedicated electric motors.
Main hydraulic loads in an aircraft are hydraulic actuators connected to control surfaces such as ailerons, elevons and rudders, as well as landing gear actuators and cargo door actuators. During start and landing phases, high lift systems are commonly used for increasing the lift coefficient of the aircraft. Typically, high lift systems of commercial and military aircraft are powered by a drive system with a central power control unit (PCU), wherein the PCU may include at least one hydraulic motor.
Other objects, desirable features and characteristics will become apparent from the subsequent summary and detailed description, and the appended claims, taken in conjunction with the accompanying drawings and this background.